Quercetin-rich Onion and the Preventive Effects on Lifestyle-related Diseases and Cognitive Decline

Abstract

Flavonols are a class of flavonoids that consist of a large group of polyphenols. Epidemiological studies have suggested that flavonols, including quercetin, have a protective effect against cardiocascular diseases. Onions are the major food source of quercetin in Japan. The mean estimated quercetin intakes by residents of a town in Japan were 15-16 mg (as quercetin aglycon) / day in summer and winter. Recently, quercetin-rich onion ‘Quergold’ containing about 75 mg quercetin / 100 g of fresh weight in the edible portion is registered. Dietary patterns have been reported to be associated with risks of dementia and Altzheimer’s diseases. Dietary administration of quercetin was shown to improve the cognitive function in both Altzheimer’s disease model mice and healthy aged mice. The results of intervention trials suggested that consumption of quercetin rich onion improved memory recall in early-stage Alzheimer’s patients, and cognitive function in elderly people. Quercetin-rich onion is expected to be contribute to prevent lifestyle-related diseases and cognitive decline through dietary life.